The auto requires the use of JASO-FD rated oil (extremely low ash). Engine blow-by picks up oil vapour which is passed out the Positive Crankcase Ventilation (PCV) system and fed into the intake just in front of the turbocharger compressor, which is why you'll sometimes see a little black oil in there. This oil is ingested by the motor, combusted and fed out the exhaust.
If you have a DPF fitted (many autos had these, 2006 to early 2010 models at least), the DPF would be filled by the ash produced and a regen cycle would NOT be able to clean it, requiring the possible manual removal and cleaning (several hundred $) or the replacement (about $4,000) of the DPF.